#!/bin/sh

#**************************************************************************
#*                                                                        *
#*                                 OCaml                                  *
#*                                                                        *
#*           Damien Doligez, projet Gallium, INRIA Rocquencourt           *
#*                                                                        *
#*   Copyright 2012 Institut National de Recherche en Informatique et     *
#*     en Automatique.                                                    *
#*                                                                        *
#*   All rights reserved.  This file is distributed under the terms of    *
#*   the GNU Lesser General Public License version 2.1, with the          *
#*   special exception on linking described in the file LICENSE.          *
#*                                                                        *
#**************************************************************************

# check-typo - Check typographic conventions on OCaml sources.

# This program will check files for the following rules:

# - absence of TAB characters (tab)
# - absence of non-ASCII characters (non-ascii)
# - absence of non-printing ASCII characters (non-printing)
# - absence of white space at end of line (white-at-eol)
# - absence of empty lines at end of file (white-at-eof)
# - presence of a LF character at the end of the file (missing-lf)
# - maximum line length of 80 characters (long-line)
# - maximum line length of 132 characters (very-long-line)
# - presence of a copyright header (missing-header)
# - absence of a leftover "$Id" string (svn-keyword)

# Exceptions are handled with git attributes: "typo.*".
# Its value for a given file is a comma-separated list of rule names,
# which lists the rules that should be disabled for this file.
# The rule names are the ones shown above in parentheses.

# Built-in exception:
# - Any file git identifies as binary
#   is automatically exempt from all the rules.

# ASCII characters are bytes from 0 to 127.  Any other byte is
# flagged as a non-ASCII character.

# For the purpose of this tool, printing ASCII characters are:
# - the non-white printable ASCII characters (33 to 126)
# - TAB (09)
# - LF (10)
# - SPC (32)
# Anything else is flagged as a non-printing ASCII character.

# This program will recursively explore the files and directories given
# on the command line (or by default the current directory), and check
# every file therein for compliance to the rules.

# Directories named .git (and their contents) are always ignored.
# This program ignores any file that is not under git control, unless
# explicitly given on the command line.

# If a directory has the git attribute "typo.prune" then it and its contents are
# ignored.

# You can ignore a rule by giving the option -<rule> on the command
# line (before any file names).

# Files which include the utf8 rule will be validated using grep and line-length
# computations will take UTF-8 sequences into account. As a special case, UTF-8
# sequences are always allowed in the copyright headers.

# First prevent i18n from messing up everything.
export LC_ALL=C

OCAML_CT_CAT=${OCAML_CT_CAT:-cat}
OCAML_CT_LS_FILES=${OCAML_CT_LS_FILES:-git ls-files}
OCAML_CT_HEAD=${OCAML_CT_HEAD:-HEAD}
OCAML_CT_AWK=${OCAML_CT_AWK:-awk}
if [ -z "${OCAML_CT_GIT_INDEX+x}" ] ; then
  OCAML_CT_GIT_INDEX=
else
  OCAML_CT_GIT_INDEX="GIT_INDEX_FILE=$OCAML_CT_GIT_INDEX"
fi

# The output of processing the attributes should be whitespace-separated with
# - the "typo." prefix dropped
# - unset/false keys not present
# - set/true keys present
# - "may" keys present, suffixed by a question mark
#
# for example,
#   typo.long-line: set
#   typo.missing-header: may
#   typo.very-long-line: false
# should result in "long-line missing-header?"
get_attrs() {
  env $OCAML_CT_GIT_INDEX git check-attr --all $OCAML_CT_CA_FLAG "$1" \
  | grep -o " typo\\..*$" | sed "s/ typo\\.//g" \
  | grep -v ": unset" | grep -v ": false" \
  | sed "s/: set//g" | sed "s/: true//g" | sed "s/: may/?/g"
}

# empty if the path is *not* pruned
check_prune() {
  env $OCAML_CT_GIT_INDEX git check-attr typo.prune $OCAML_CT_CA_FLAG "$1" \
  | grep -v ': unspecified$' | grep -v ': false$'
}

# Special case for recursive call from the find command (see IGNORE_DIRS).
case "$1" in
  --check-prune)
    case $2 in
      .git|.git/*)
          echo "INFO: pruned path $2 (.git)" >&2
          exit 0;;
    esac
    if test -n "$(check_prune "$2")"; then
        echo "INFO: pruned path $2 (typo.prune)" >&2
        exit 0
    fi
    exit 3;;
esac

case "$1" in
  --get-attrs)
      get_attrs "$2"
      exit 0;;
esac

usage () {
  echo "usage: check-typo {-<rule>} [--] {<file-or-dir>}" >&2
  exit 2
}

check_script () {
  if [ "$($OCAML_CT_CAT "$OCAML_CT_PREFIX$1" \
            | sed -ne '1s/^#!.*/#!/p')" != '#!' ] ; then
    # These files are listed manually, rather than via gitattributes,
    # because the list should never expand, and it should not be trivial to
    # expand (the unix-execvpe test is an ultra-special-case!)
    f=${1#./}
    if [ "$f" != "boot/ocamlc" ] && [ "$f" != "boot/ocamllex" ] && \
       [ "$f" != "testsuite/tests/lib-unix/unix-execvpe/subdir/script2" ] ; then
      echo "$1 shouldn't be executable; either:"
      echo " - Add a #! line"
      echo " - Run chmod -x $1 (on Unix)"
      echo " - Run git update-index --chmod=-x $1 (on Windows)"
      echo "You may wish to check your core.fileMode setting"
      EXIT_CODE=1
    fi
  fi
}

userrules=''

while : ; do
  case "$1" in
    -help|--help) usage;;
    -*) userrules="${1#-} $userrules"; shift;;
    --) shift; break;;
    *) break;;
  esac
done

IGNORE_DIRS="
  -name .git -prune -o
  -type d -exec $0 --check-prune {} ; -prune -o
"
# `-type d`: simple files (not directories) are not pruned during the
# "find" invocation but below (look for "check_prune") for performance
# reasons: most files outside pruned directories are not pruned, so it
# is faster to optimistically run check-typo on them (and maybe get
# out in the middle) than to first check then run.

TEST_AWK='BEGIN {if ("a{1}" ~ /a{1}$/) exit 1}'
if ! $OCAML_CT_AWK "$TEST_AWK" ; then
  if $OCAML_CT_AWK --re-interval "$TEST_AWK" 2>/dev/null ; then
    OCAML_CT_AWK="$OCAML_CT_AWK --re-interval"
  else
    echo "This script requires interval support in regexes ({m} notation)">&2
    echo "Please install a version of awk (e.g. gawk) which supports this">&2
    exit 2
  fi
fi

EXIT_CODE=0
( case $# in
    0) find . $IGNORE_DIRS -type f -print;;
    *) for i in "$@"; do find "$i" $IGNORE_DIRS -type f -print; done;;
  esac
) | (
  while read f; do
    if test -n "$(check_prune "$f")"; then continue; fi
    if $(git check-ignore -q "$f"); then continue; fi
    case `$OCAML_CT_LS_FILES "$f" 2>&1` in
      "") path_in_index=false;;
      *) path_in_index=true;;
    esac
    case "$*" in
      *$f*) is_cmd_line=true;;
      *) is_cmd_line=false;;
    esac
    if [ -z "$OCAML_CT_PREFIX" ] ; then
      if [ -x "$f" ] ; then
        check_script "$f"
      fi
    else
      if git ls-files -s "$f" | grep -q "^100755" ; then
        check_script "$f"
      fi
    fi
    if $path_in_index || $is_cmd_line; then :; else continue; fi
    attr_rules=''
    if $path_in_index; then
      # Below is a git plumbing command to detect whether git regards a
      # particular file as binary. This takes into account .gitattributes, but
      # also works if the file has been automatically detected as binary by git.
      # EMPTY is the hash of the empty tree (which is specially known to git -
      # it is automatically included in every repository) as a way to get
      # `diff-tree` to print the whole tree state; its `--numstat` output then
      # prints a summary where two dashes in the first two columns indicates a
      # binary file.
      #   (See https://git-scm.com/docs/git-diff-tree#_other_diff_formats and
      #    the documentation for the --numstat option. Commands designated as
      #    "plumbing" commands in git have stable output intended for parsing)
      EMPTY=`git hash-object -t tree /dev/null`
      git diff-tree --numstat $EMPTY $OCAML_CT_HEAD -- "$f" \
        | grep -q "^-[[:blank:]]-" && continue
      attr_rules=$(get_attrs "$f")
    fi
    rules="$userrules"

    # remove newlines, ensure spaces at boundary
    rules=" $(echo $rules) "
    attr_rules=" $(echo $attr_rules) "

    if test -n "$(echo "$rules $attr_rules" | grep " utf8 ")"
    then
        # grep -a is used to force the file to be considered as text and -x
        # requires the entire line to match. This specifically detects the
        # presence of lines containing malformed UTF-8. It may be tested using
        # https://www.cl.cam.ac.uk/~mgk25/ucs/examples/UTF-8-test.txt
        if $OCAML_CT_CAT "$OCAML_CT_PREFIX$f" \
             | LC_ALL=en_US.UTF8 grep -qaxv '.*' ; then
          echo "File \"$f\" is not correctly encoded in UTF-8"
          exit 2
        fi
    fi
    if ! \
    ($OCAML_CT_CAT "$OCAML_CT_PREFIX$f" | tr -d '\r'; echo) \
    | $OCAML_CT_AWK -v rules="$rules" -v attr_rules="$attr_rules" -v file="$f" \
      '
        function is_err(name) {
          return ((rules attr_rules) !~ (" " name "[\\? ]"));
        }

        function report_err(name, msg) {
          printf ("%s:%d.%d:", file, NR, RSTART + RLENGTH);
          printf (" [%s] %s\n", name, msg);
          got_errors = 1;
        }

        function err(name, msg) {
          ++ counts[name];
          if (is_err(name) && counts[name] <= 10) {
            report_err(name, msg);
            if (counts[name] == 10){
              printf ("WARNING: too many [%s] in this file.", name);
              printf ("  Others will not be reported.\n");
            }
          }
        }

        function err_if(guard, name, msg) {
          if (is_err(guard)) {
            err(name, msg);
          } else {
            ++ counts[name];
          }
        }

        function more_columns(str, limit,       c){
          c = 0;
          for (i = 1; i <= length(str); i++){
            if (substr(str, i, 1) == "\t"){
              c = int((c + 8) / 8) * 8;
            }else{
              ++ c;
            }
          }
          return c > limit;
        }

        function utf8_decode(str) {
          if (is_err("utf8")) {
            return str;
          } else {
            # This script assumes that the UTF-8 has been externally validated
            t = str;
            gsub(/[\300-\367][\200-\277]+/, "?", t);
            if (t != str) {
              ++ counts["utf8"];
            }
            return t;
          }
        }

        BEGIN { state = "(first line)"; in_recipe = 0; in_continuation = 0; }

        # Makefile recipe automaton

        # in_continuation == 1 if the line ends with a backslash
        # in_recipe is:
        #   0 - not in a recipe
        #   1 - target line scanned, but not yet seen first recipe line
        #   2 - scanning recipe lines

        # Non-recipe line
        match($0, /^[^\t#] *[^# ]/) {
          if (!in_continuation) {
            if (!match($0, /^(ifn?eq|else|endif)/)) {
              in_recipe = 0;
            }
          }
        }

        # target: or target:: line
        match($0, /^[^#]*[^:#]::?($|[^=])/) {
          if (!in_continuation) {
            in_recipe = 1;
          }
        }

        match($0, /^\t[^\t]+$/) {
          if (in_recipe == 0 \
              || in_recipe == 1 && in_continuation \
              || is_err("makefile-whitespace")) {
            err("tab", "TAB character(s)");
          } else {
            ++ counts["makefile-whitespace"];
            in_recipe = 2;
          }
        }

        match($0, /.$/) {
          in_continuation = (substr($0, length($0)) == "\\");
        }

        match($0, /.\t/) {
          err("tab", "TAB character(s)");
          t = utf8_decode($0);
          if (more_columns(t, 80)){
            RSTART=81;
            RLENGTH = 0;
            err_if("very-long-line", "long-line", "line is over 80 columns");
          }
          if (more_columns(t, 132)){
            RSTART=133;
            RLENGTH = 0;
            err("very-long-line", "line is over 132 columns");
          }
        }

        match($0, /[\200-\377]/) \
        && state != "authors" && state != "copyright" {
          if (is_err("utf8")) {
            err("non-ascii", "non-ASCII character(s)");
            if (header_utf8 && !is_err("non-ascii")) {
              err("non-ascii-utf8", \
                  "non-ASCII character(s) AND UTF-8 encountered");
            }
          } else {
            ++ counts["utf8"];
          }
        }

        match($0, /[^\t\200-\377 -~]/) {
          err("non-printing", "non-printing ASCII character(s)");
        }

        match($0, /[ \t]+$/) {
          err("white-at-eol", "whitespace at end of line");
        }

        match($0, /\$Id(: .*)?\$/) {
          err("svn-keyword", "SVN keyword marker");
        }

        $0 !~ /\t/ && length($0) > 80 {
          t = utf8_decode($0);
          sub(/https?:[A-Za-z0-9._~:\/?#\[\]@!$&\047()*+,;=%-]{73,}$/, "", t);
          if (length(t) > 80) {
            RSTART = 81;
            RLENGTH = 0;
            err_if("very-long-line", "long-line", "line is over 80 columns");
          }
        }

        $0 !~ /\t/ && length($0) > 132 {
          RSTART = 133;
          RLENGTH = 0;
          t = utf8_decode($0);
          if (length(t) > 132) {
            err("very-long-line", "line is over 132 columns");
          }
        }

        # Record that the header contained UTF-8 sequences
        match($0, /[\300-\367][\200-\277]+/) \
        && (state == "authors" || state == "copyright") {
          header_utf8 = 1;
          if (counts["non-ascii"] > 0 && is_err("non-ascii")) {
            err("non-ascii-utf8", \
                "non-ASCII character(s) AND UTF-8 encountered");
          }
        }

        # Header-recognition automaton. Read this from bottom to top.
        # Valid UTF-8 chars are recognised in copyright and authors
        # TODO: ensure all files are valid UTF-8 before awking them.
        # Note that this code also assumes that combining characters are NOT
        # used (i.e. that every Unicode code-point corresponds to exactly
        # one displayed character, i.e. no Camels and no including
        # weird-and-wonderful ways of encoded accented letters).

        state == "close" && $0 ~ /\*{74}/ { state = "OK"; }
        state == "close" { state = "(last line)"; }
        state == "blurb" && $0 ~ /\* {72}\*/ { state = "close"; }
        state == "blurb" && $0 ~ /\/LICENSE/ { state = "(license path)" }
        state == "blurb1" && $0 ~ /\*   All rights reserved. .{47} \*/ \
                                                 { state = "blurb"; }
        state == "blurb1" { state = "(blurb line 1)"; }
        state == "copyright" && $0 ~ /\* {72}\*/ { state = "blurb1"; }
        state == "copyright" \
          && $0 !~ /\*   Copyright [0-9]{4}([\300-\367][\200-\277]+|.){54} \*/ \
          && $0 !~ /\*     ([\300-\367][\200-\277]+|.){66} \*/ \
                      { state = "(copyright lines)"; }
        state == "authors" && $0 ~ /\* {72}\*/ { state = "copyright"; }
        state == "authors" \
          && $0 !~ /\* ([\300-\367][\200-\277]+|.){70} \*/ \
                      { state = "(authors)"; }
        state == "blank2" && $0 ~ /\* {72}\*/ { state = "authors"; }
        state == "blank2" { state = "(blank line 2)"; }
        state == "title" && $0 ~ /\* {33}OCaml {34}\*/ { state = "blank2"; }
        state == "title" { state = "(title line)"; }
        state == "blank1" && $0 ~ /\* {72}\*/ { state = "title"; }
        state == "blank1" { state = "(blank line 1)"; }
        state == "(first line)" && NR < 4 && $0 ~ /\*{74}/ { state = "blank1"; }

        {
          prev_line = last_line;
          last_line = $0;
        }

        END {
          if (match(last_line, /.+/)){
            err("missing-lf", "missing linefeed at EOF");
            prev_line = last_line;
            ++ NR;
            empty_file = 0;
          }else{
            empty_file = NR == 1;
          }
          if (!empty_file && match(prev_line, /^$/)){
            err("white-at-eof", "empty line(s) at EOF");
          }
          if (state != "OK"){
            if (NR >= 10){
              NR = 1;
              RSTART = 1;
              RLENGTH = 0;
              err("missing-header", sprintf("bad copyright header %s", state));
            }else{
              counts["missing-header"] = 1;
            }
          }
          split(attr_rules, r, "[? ]");
          for (i in r){
            name = r[i];
            if (name != "" && !counts[name]){
              NR = 1;
              RSTART = 1;
              RLENGTH = 0;
              if (attr_rules !~ (" " name "\\? ")) {
                report_err(name,
                  sprintf("attribute is unused", name));
              }
            }
          }
          exit got_errors;
        }
      ' ; then
        EXIT_CODE=1
      fi
  done
  exit $EXIT_CODE
)
